<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .div01{
            width: 100px;
            height: 100px;
            background-color: red;
        }

    </style>
</head>
<body>
<div class="div01"></div>



</body>
</html>